Background: Success rates for surgical management of chronic exertional compartment syndrome (CECS) are historically lower with release of the deep posterior compartment compared with isolated anterolateral releases. At our institution, when a deep posterior compartment release is performed, we routinely examine for a separate posterior tibial muscle osseofascial sheath and release it if present. Purpose: Within the context of this surgical approach, the aim of the current study was to compare long-term patient satisfaction and activity levels in patients who underwent 2-compartment fasciotomy versus a modified 4-compartment fasciotomy for CECS. Study Design: Cohort study; Level of evidence, 3. Methods: Patients treated with fasciotomy for lower extremity CECS from 2007 to 2017 were retrospectively identified. In all patients in whom a 4-compartment fasciotomy was indicated, the tibialis posterior muscle was examined for a separate osseofascial sheath, which was released when present. Patients completed a series of validated patient-reported outcome (PRO) surveys, including the Marx activity score, Tegner activity score, 12-Item Short Form Health Survey, and Likert score for patient satisfaction. Results: Of the 48 patients who were included in this study, 34 (71%) patients with a total of 52 operative limbs responded and completed PRO surveys. The mean follow-up for the entire cohort was 5.5 ± 2.6 years. Of the 34 patients, 23 (68%) underwent 2-compartment fasciotomy and 11 (32%) underwent 4-compartment fasciotomy. Among the patients in the 4-compartment fasciotomy group, 7 (64%) were found to have a fifth compartment. No significant difference was found in any of the validated PRO measures between patients who had a 2- versus 4-compartment fasciotomy or those who underwent 4-compartment fasciotomy with or without a present fifth compartment. At a mean 5.5-year follow-up, 74% of patients who underwent a 2-compartment release reported good or excellent outcomes compared with 82% of patients who underwent our modified 4-compartment release. Conclusion: The current study, which included the longest follow-up on CECS patients in the literature, demonstrated that the addition of a release of the posterior tibial muscle fascia led to no significant difference in PRO measures between patients who underwent a 2- versus 4-compartment fasciotomy, when historically the 2-compartment fasciotomy group has had higher success rates.